"We have moved away from the systems nature has provided to us, it's time we move back," says Ooze cofounder Eva Pfannes.

Between the Waters was a collaboration between Ooze and artist Marjetica Potrč. Courtesy Roman Mensing

On a small strip of land between the Emscher River and the Rhine Herne Canal in Germany once sat a rest stop whose colorful appearance belied its radical purpose. The structure’s artful design consisted of pipes leading from two toilets and the Emscher (the most polluted river in Germany) that converged at a small community garden and drinking fountain. The garden was, in fact, a manmade wetland that collected, treated, and cleaned the effluence from the toilets and river—making it drinkable.

The 2010 project, known as Between the Waters, was one of the earliest projects of Rotterdam-based Ooze Architecture and its two founders Eva Pfannes and Sylvain Hartenberg. Ooze is focused on one very specific goal: finding solutions to the world’s clean water crisis through observing, imitating, and socially normalizing naturally-occurring water purification processes. “The solutions are already there, they’ve always been there, ingrained in nature,” says Hartenberg. “We just use these ideas the environment has presented to us all along, and modify them to make systems that are efficient, low-tech, and easily maintained.”

The constructed wetland—the filtration system on display at Between the Waters—exemplifies the kind of system that Ooze uses often. This artificially-created landscape operates like a sieve by using sediment and vegetation break down toxic substances. But unlike a naturally-occurring wetland, these landscapes use specific sediments and plants that optimize conditions for desirable microorganisms (and deter bugs and odorous bacteria). But it’s not a cure-all for the world’s clean water shortage: Different landscapes and climates require different solutions. Moreover, Pfannes and Hartenberg know that many clients and communities will doubt their proposals. “We wanted to have smaller-scale examples we could point to when bidding for a project or approaching a municipality,” says Pfannes. “They can always be scaled up depending on population.”

“We have been so far from nature for so long, all our filtration systems are hidden underground for most of the world. We don’t have to face them,” says Pfannes. Projects such as Between the Waters therefore have been key to proving their methodology for sterilizing water is clean and safe to drink. Courtesy Ooze

That scaling up has manifested itself in several projects since Between the Waters, including a 2012 project in which the duo introduced their work to members of the Rio de Janeiro government as a way to solve the city’s ongoing struggle for clean water in its slum-like unplanned settlements, known as favelas. “They were extremely interested in the work we were doing, but they had absolutely no money to make it happen,” says Hartenberg “So basically they said, ‘If you can find the money we will support you in this radical idea.’”

And so the architects set off to find funding and realize their prototypes. They spent the project’s first two years speaking with activists, inhabitants, community leaders, and ecologists to better understand the issues plaguing the area. “We let people explain all their problems around water themselves, so that became the documentary [film], and based on that, we gave our solutions to the neighborhoods and presented to the funders [in Europe],” says Pfannes.

The Água Carioca prototype in Rio de Janeiro. “It’s not a solution we think would work for the entire city. But we saw these very specific circumstances in the favelas where there was huge pools of wastewater, kids were getting sick, they were acting as informal gang territories,” said Pfannes. “So we thought, why not replace these cesspools with a beautiful piece of nature that also provides clean drinking water for a very low cost?” Courtesy Raul Correa Smith

The solution, named Água Carioca, was essentially a larger version of Between the Waters spread over a single site in a Rio de Janeiro favela. Due to the city’s nearby protected rain forests, transporting waste outside the city was out of the question. “We had to solve the problem right where it was, and right where the water was being consumed,” says Pfannes.

This is where the constructed wetland came into play: The wetland requires approximately five square feet to filter one person’s waste per day. And with pools of wastewater already occupying a great deal of space within the favelas, Pfannes and Hartenberg knew they had room to operate. Ooze’s prototype would filter the effluence of around 150 people per day (that’s roughly 646 gallons) sourced from the favela’s polluted streams and ponds. Ooze received a $30,000 grant from the Stimuleringsfonds foundation to build the first prototype in Rio at Sítio Roberto Burle Marx, a garden on the outskirts of Rio. The design was realized, but further plans to serve the entire municipal district have been put on hold because of political roadblocks.

Shortly thereafter, Hartenberg and Pfannes began working on a proposal for the Dutch Government’s ‘Water as Leverage‘ program. The proposal would focus on working with the municipality of Chennai, India to strategize against flooding and drought. Due to an intensely wet two-month rainy season, an incomplete underground drainage system, and lack of surface permeability (Chennai is densely built), the city suffers from chronic extreme flooding—deluges that leave pools of toxic, undrinkable water everywhere. The ensuing dry season brings acutes droughts.

Once again, the architects turned to the natural environment for their solution. Through conversations with long-term residents and experts, and analyzing the region’s current and historic landscape, the Hartenberg and Pfannes learned of a water management strategy implemented by the Mughals in the 17th and 18th century, who dug thousands of ditches that slowly allow rainwater to permeate the earth and restore the city’s aquifers. From there, the purified water could be pumped with wells. “With urbanization, this system was forgotten,” says Pfannes. “They built over the lakes and diverted the water where it is basically lost forever; again, we have moved away from the systems nature has provided to us.”

Ooze’s proposal for Chennai consisted of similar catchment pools throughout the city. True to form, constructed wetlands also make an appearance in the plan: In several places, they would assist in the filtration process. The project, aptly named City of 1,000 Tanks, will take an incremental approach to implementation. “People need to get used to the idea of their water being filtered out in the open,” says Hartenberg. It is currently being tested on scales ranging from 8,000 to 400,000 residents throughout the city.

Diagrammatic section of City of 1,000 Tanks, showing water seep from catchments and wetlands into the underground aquifer. From there, it can be pumped to the surface via individual well holes. Courtesy Ooze

Most recently, the duo were invited by the Brooklyn design center A/D/O to develop and present a solution for New York’s wastewater challenges. The metropolis has a combined sewer-rainwater draining system that’s frequently overwhelmed by rain, leading to discharges of mixed stormwater and sewage into the East River and other natural water bodies. Ooze’s Every Other Street proposal recommends turning thousands of city streets into porous surfaces that absorbs rainwater, thereby reducing overflows and the city’s dependence on hard infrastructure.

Diagram of New York brownstone block from Every Other Street Courtesy Ooze

Although the wide-spread realization of Every Other Street is far-fetched, the project highlights how a return to nature could benefit highly-planned New York the same way it has aided Rio de Janeiro and Chennai. “By just bringing New York and New Yorkers a little closer to nature through the redesign of their streets, we have the power to prevent pollution, and impart an improved lifestyle all at once,” says Hartenberg. “It’s just about listening to what nature wants.”